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| Titel |
Inter-annual variability in atmospheric nitrous oxide over the past two decades |
| VerfasserIn |
R. L. Thompson, P. Bousquet, F. Chevallier, S. Zaehle, L. Bopp, E. Dlugokencky |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250070683
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| Zusammenfassung |
| Nitrous oxide (N2O) concentrations have been steadily increasing in the atmosphere over the past few decades at a rate of approximately 0.3% per year. This trend is of major concern as N2O is both a long-lived greenhouse gas and an Ozone Depleting Substance (ODS). This trend is largely due to the increased input of reactive nitrogen (Nr) to the environment, primarily in N-fertilizers. Before the widespread usage of N-fertilizers, the naturally occurring N2O source was approximately balanced by the atmospheric sink, that is, photochemical destruction in the stratosphere. Super-imposed on the atmospheric trend, is significant inter-annual variability (IAV), which is thought to be mainly determined by inter-annual variations in stratosphere-troposphere exchange.
Using global N2O records since the late 1990’s (when more than 50 stations are available worldwide), we found significant IAV in the N2O atmospheric growth-rate with a positive anomaly from 1998 to 1999 in the northern hemisphere and a negative anomaly in 2003 in Europe, North America and Asia. To test the influence of the inter-annual variations in emissions versus stratosphere-troposphere exchange on the observed growth-rate, we carried out simulations using the global circulation model, LMDZ4, which was driven using ECMWF reanalysis data and was coupled to emissions estimates from the global eco-system model, Orchidee O-CN and the ocean biogeochemistry model, PISCES, which were also driven by climate data. |
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